Dorsiflexion shoe

ABSTRACT

A high performance dorsiflexion shoe has a sole and a constraining device above the metatarsal-phalangeal joint. The sole has a ground-contacting surface, a forefoot region, a midfoot region and a heel portion. The forefoot region is made of a high density material, and has a thickness, measured in a direction perpendicular to the ground-contacting surface of the sole, greater than the thickness of the heel portion, thereby defining a characteristic angle of declination from the forefoot region to the heel portion. The constraining device substantially constrains a wearer&#39;s metatarsal-phalangeal joints from movement when exercising. The forefoot region has a curved form defined so as to further minimize flexion of the metatarsal-phalangeal joint.

BACKGROUND OF THE INVENTION

This invention relates to shoes, and, more particularly, to leisure andathletic shoes that promote dorsiflexion.

In standard shoes, the metatarsal phalangeal joints remain in a bendposition at take-off and is unable to generate any energy during jumpingand only a very small amount of energy during running due to the factthat the shoe does not straighten until after take-off when any returnof energy is too little, too late, having no influence on performance.The used energy is therefore lost and useless for aiding propulsion injumping or running. Over the past years, specialized track and fieldshoes have progressed in that they have begun to have relatively stiffmidsoles.

In contrast, general athletic shoe manufacturers seem to be movingtoward running shoes that are more flexible at the metatarsal phalangealjoint by either increasing the flexibility of materials used in theirmanufacture or by modifying the structure of the midsole (e.g.,incorporating flexion grooves). This, unfortunately, has no benefit withrespect to propulsive performance and is driven by pre-conceivednotions.

During athletic activities, analysis of resultant joint moments andjoint power indicate that for each joint, there are phases when energyis absorbed and phases when energy is generated. If the absorbed energyis dissipated and not stored for later re-use, it is wasted (i.e., itmerely generates heat). If the stored energy can be reused, thenperformance can be increased.

The metatarsal phalangeal joint is one joint which, heretofore, has beena sink for energy dissipation and very little energy generation at orbefore take-off. This is because an athlete's foot rolls onto theforefoot and does not plantarflex until after take-off.

U.S. patent application Ser. No. 09/833,485 to Whatley, the content ofwhich is herein incorporated by reference thereto, describes a shoe thatutilizes dorsiflexion in an effort to increase the working of thecertain muscles during exercise, with particular emphasis on enabling alarger range of motion of the foot so as to better work the calf.Dorsiflexion is brought about by a shoe which is inclined backwards(i.e., declined) to that of a normal plantar shoe. Essentially, insteadof the heel being supported at a point higher than the toe, the inverseis true, with the angle of reverse incline being approximately 10degrees. The shoe has proven to be extraordinarily stable. However, theincline of 10 degrees and the particular clumsy appearance of the shoehave limited its marketability and usefulness to all but those who areprofessional athletes.

Because of the dorsiflexion, one must ensure a rolling effort of thefoot in order to avoid harm to the user's musculature and joints. Theform of the sole, in which, in a forward end of the sole, the sole isthicker and of a cylindrical form, is such that it approximates thenatural rolling effect of the foot. FIG. 21A of the above-mentionedpatent application shows a shoe which most nearly approaches that of theinvention.

What is needed is an athletic shoe that takes advantage of the energygeneration capacity of the metatarsal phalangeal joint. Further, what isneeded is an improved dorsiflexion shoe that takes better advantage ofthe mechanism of dorsiflex action in order to gain improved poweroutput, comfort and performance. Still further, what is needed is adorsiflex shoe that has a more conventional form, in order to improvethe marketability and comfort of the shoe.

SUMMARY OF THE INVENTION

A high performance dorsiflexion shoe has a shell, an upper, and aconstraining device above the metatarsal-phalangeal joint. The shell hasa sidewall portion connected to a sole portion. The sole portion has aground-contacting surface, a forefoot region, a midfoot region and aheel portion. The forefoot region is made of a high density material,and has a thickness, measured in a direction perpendicular to theground-contacting surface of the sole, greater than the thickness of theheel portion, thereby defining a characteristic angle of declinationfrom the forefoot region to the heel portion, when the wearer is in astanding position. The constraining device substantially constrains awearer's metatarsal-phalangeal joints from movement when exercising. Theforefoot region has a curved form defined so as to further minimizeflexion of the metatarsal-phalangeal joint.

In another feature, the angle of declination is between 1 degree to 15degrees, preferably 5 degrees.

In another feature, the shoe includes a reinforced, padded toe portion.

In another feature, the heel portion is substantially comprised of a lowdensity, viscous-like material, adapted for fitness and training shoes.

In another feature, the sidewall of the shell is formed so as to givethe impression that the shoe is a conventional plantarflex shoe.

In a further advantage of the invention, the 5 degree dorsiflex angleproduces a shoe that appears more conventional (plantar flex) and thusto be significantly less clumsy, more natural and comfortable, andtherefore, much more likely to be purchased and used by amateur athletesas well as professional athletes.

In another advantage, the fact that the angle of reverse incline islesser with the invention as compared to dorsiflex shoes of the priorart, less material is required in the manufacture. Less material equatesto less cost in manufacture as well as a lower minimum weight to theshoe.

In another advantage, the shoe of the invention is capable ofinterfacing with interchangeable insoles of various weight, energyabsorption capacity, and rigidity, thus enabling the wearer a greaterflexibility in configuring the invention for a particular type of sportsactivity. Further, the fact that the minimum weight has been reduced,due to the reduced bulk in the sole, means that an even greater range ofweight of the shoe is possible.

In a further advantage, the shoe is configured to receive insoles whichadjust the thickness of the rear of the shoe from extreme dorsiflex toplantarflex, thus avoiding morphological problems which occur where aninsole is designed so as to increase the thickness of the forwardportion of the sole from plantarfex to dorsiflex.

In another advantage, the invention eliminates the need for themetatarsal-phalangeal joint to flex because the shoe itself reproducesthe movement of this joint and the toes.

In another advantage, the invention improves the capacity of the foot byimproving its efficiency while minimizing the risk to harm to the footby making the shoe out of materials that absorb stress and byreproducing the rolling motion of the foot.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of the shoe of the invention.

FIG. 2A is a section view taken along line A-A of FIG. 1, showing theconstraining strap of the invention in an uncinched position.

FIG. 2B is a section view taken along line A-A of FIG. 1, showing theconstraining strap of the invention in a cinched position.

FIG. 3A is a cut-away view showing the reinforced toe region of theinvention.

FIG. 3B is a perspective view of the reinforced, high density platedisposed in the forefoot region of the sole of the invention.

FIGS. 4A to 4B are partial cut away/cross sectional, longitudinal viewsof the invention showing two configurations of interchangeable insoles.

FIG. 5A is a side view of another embodiment of the invention showing ahybrid sole in which the sole thickness is substantially constant alongits length.

FIG. 5B is a side view of hybrid shoe of FIG. 5A in which the heelportion is deformed under the weight of use, in order to create adorsiflex configuration.

FIG. 6 is a side view of another embodiment of the invention, having aninterchangeable heel portion.

FIG. 7A is a cross-sectional side view of another embodiment of theinvention having a composite sole assembly.

FIG. 7B is a bottom view of the embodiment of FIG. 7A.

FIG. 8 is a cross-sectional side view of another embodiment of theinvention.

FIG. 9A is a table showing different embodiments of the power plate ofthe invention.

FIG. 9B is a top view of a power plate of the invention.

FIG. 10A is a top view of an insole of the invention.

FIG. 10B is a cross-sectional side view, taken along line B-B of FIG.10A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the preferred embodiment, as shown in FIG. 1, a high performancedorsiflexion shoe 10 has a shell 12, an upper 14, and a constrainingdevice 16 above the metatarsal-phalangeal joint 20. The shell 12 has asidewall portion 22 with an upper edge 13. The sidewall portion 12 isconnected to a sole portion 24. The sole portion 24 has aground-contacting surface 26, a forefoot region 30, a midfoot region 32and a heel portion 34. The forefoot region 30 is made of a high densitymaterial, and has a thickness T, measured in a direction perpendicularto the ground-contacting surface 26 of the sole portion 24, greater thanthe thickness t of the heel portion 34, thereby defining acharacteristic angle α of declination from the forefoot region 30 to theheel portion 34. The constraining device 16 substantially constrains awearer's metatarsal-phalangeal joints 20 from movement when exercising.The forefoot region 30 has a curved region 28 defined so as to furtherminimize flexion of the metatarsal-phalangeal joint 20.

The angle α of declination may vary significantly, from between 1 degreeand 15 degrees. The preferred angle is 5 degrees.

Referring now to FIGS. 2A and 2B, the constraining device 16, just belowthe upper 14 of the shoe 10, above the metatarsal-phalange joint 20 ofthe wearer, restrains the top 36 of the foot 40 against the sole portion24 in order to prevent this unfruitful or wasted motion (and thusprevent energy waste). A cinchable strap 42 having one end 44 connectedadjacent the metatarsal-phalangeals 16 and the other end 46 threadedthrough a loop 50 attached to the opposite side 52 of the metatarsalphalangeals, transverse to the connection point 54, has an extreme end56 which includes a “VELCRO”™ backing 60 that mates with a correspondingbacking 61 on the upper, such interlocking “VELCRO”™ arrangementenabling locking of the strap in place after cinching. Note that thestrap may be fabricated as part of the tongue, be attached to theoutsole, and vary in width. Further, any known attachment arrangementmay be used. Still further, a rigid comfort insert (not shown) may beattached between the strap 16 and the foot 40, the insert substantiallyconforming to the shape of the top of the foot above themetatarsal-phalangeal 20, thus increasing the comfort of the strap as itis cinched firmly against the metatarsal-phalangeal joint.

Referring now to FIG. 3A, as one tries to maximize the lever, highstresses are applied in the toe region 62 of the shoe 10, especially asthe shoe just leaves contact with the ground and thus, the foot 40(particularly the toe) must be protected. Therefore, in a feature of theinvention, the toe region 62 is padded with a compressible material 64for comfort and support and a rigid, curved power plate 66, insertmolded below the toe is made of a very high density composite material70. Note that the fact that now, the forward stress normally applied tothe region of the shoe just above the toe 62 is no longer needed torestrain the foot or absorb forces—forward forces are now absorbed bythe strap 16. Further, the high power plate 66 below the toe 62 in theregion designated by reference numeral 66 provides support so that thetoe no longer needs to support the end of the foot—this is accomplishedby the strap 16 working in combination with the power plate 66 which nowperforms the equivalent function of the toe, thus reducing fatigue ofthe foot. On the other hand, the heel portion 34 is substantiallycomprised of a low density,-viscous-like material, particularly adaptedto fitness and training shoes (note that for competition, thisviscous-like material is generally not appropriate—the actual soledesign will be made of materials which suit the intended surface andsport).

Referring now to FIG. 3B, the power plate 66 is a rigid ground effectguide which controls the running motion and effects transmission offorces to the ground and into the body of the user. The power plate 66is rigidly formed in a curved shape, having an outward facing surface80, and an inward facing surface 82, connected by a thin sidewall 84.The board 66 is optimized to reproduce, as accurately as possible, thenatural rolling effect of the foot. For aesthetic reasons, to providebetter sole life, and to ensure firm fixing of the spring broad 66 inthe softer sole portion 24 or shell 12 in the insert molding process,ribs 90 are provided in the outward facing surface 80 and extendcompletely through an endo layer 92 so as to be expose a surface 91 tothe outside of the shoe 10. Thus, the power plate 66 can be fabricatedin different colors and the integral ribs 90 will thus be visible andadd a pleasing multi-tone aspect to the shoe. The power plate 66 ispreferably made of a material, having a shore hardness of between 20 and90, whereas the endo layer 92 as well as the rest of the shell 12 ismade of standard, soft material.

The measured stiffness of the shoe 10 in the region of the power plate66 is selected so as to be in the range of 0.1N.M.Deg-1 and0.5N.M.Deg-1. The shape, length, positioning and density of the powerplate 66 vary depending on the intended sport or competitiveapplication. In order to minimize impact on the metabolic cost ofpropulsion, the weight of the power plate 66 is in the range from 30 to250 grams. Essentially, the power plate 66 is positioned so as tominimize flexing of the metatarsal phalangeal joint 20, in an effort toreduce energy loss at this joint, particularly during running andjumping.

The invention substantially reduces energy loss due tometatarsal-phalangeal flexing during running (including slow joggingfrom speeds of 2 meters/sec through fast sprinting at speeds of 10meters/sec) and jumping (including any propulsive activity fromsubmaximal hopping to maximal jumping in vertical, horizontal andlateral directions). The inventors have shown that, using the inventionas compared to a conventional plantarflex shoe, jumping performance canbe increased from 5% to 10%, and in running, by about 5%. Testing hasshown that, in jumping, the power plate 66 absorbed an average of 24 Jduring one-legged jumping, assuming a body mass of 70 Kg, whichcorresponds to a difference in jump height of approximately 3.5 cm.

Referring now to FIG. 4A, in another embodiment, an adaptabledorsiflexion shoe assembly 100 includes a shoe 102 adapted to receive aninterchangeable insole 104 which inserts into the shoe. The assembly 100results in a dorsiflexion shoe defined by a particular angle β ofdeclination. The insole 104 has weights 106 selected to provide aparticular level of energy consumption during use. The weights 106 maybe adjusted through the use of various configurations in which theweights are insert or injection molded into place in the insole 104using, for example, a composite molding process at fabrication. In thismanner, the shoe 102 of the invention is capable of interfacing withinterchangeable insoles 104 of various weight, energy absorptioncapacity, rigidity, and form thus enabling the wearer a greaterflexibility in configuring the invention for a particular type of sportsactivity corresponding to a particular angle of declination. Further, asthe inventors have learned that, surprisingly, only a small angle ofdeclination (5 degrees being ideal) contributes substantially toperformance, it is not necessary to use a design corresponding to thebulbous sole design of the prior art. The result of this is that theweight of the shoe 10, 102 has been reduced. Consequently, the bulk inthe sole portion 24 is greatly reduced and thus, an even greater rangeof weight of the shoe is possible.

Referring now to FIG. 4B, an insole 120 is shown in which corresponding,interlocking surfaces 122 and 124 help ensure that the insole does notmove during operation.

Referring now to FIG. 5A, in another embodiment 130, the foot 40 issupported level, so that the bottom of the wearer's toes are the sameheight as the bottom of his heel. However, the forefoot region 132 ofthe composite sole 134 is made from a more rigid material and the heelportion 136 of the sole is made from a soft, viscous, low density, orless rigid material. Referring now to FIG. 5B, the softness of the heelallows it to deform, under the weight of the user, much more than thatof the harder forefoot region 22′. This creates an angle Φ ofdeclination upon the deformation of the softer heel region 136, thusproviding dorsiflexion in a hybrid shoe 130 that has an appearance of anordinary shoe.

The selection of a suitable relative thickness and rigidity for thematerials used in the construction of this hybrid sole 130 is importantin order to balance the interests of providing dorsiflexion working andprotection to the heel.

Referring now to FIG. 6, in another embodiment, a dorsiflex shoe 140 isprovided having an interchangeable heel 142 adaptable to the particularsport or activity to be performed. Heels 142 of differing hardnessesconnect and disconnect to the interfacing portion of the shoe 140 via aconnection device such as a dove tail groove interface 144, asnap-in-place mechanism, or by a pin lock (not shown).

Referring now to FIGS. 7A and 7B, in another embodiment, a dorsiflexshoe 150 is provided having a composite sole arrangement. A soleassembly 152 is made up of several layers and distinct regions includinga sport-surface selected central region 154, a viscous-like heel portion156, a reinforced forefoot region 160, a high density forward region162, a medium density upper region 164, a low density region 166 in therearward part of the shoe, below the wearer's heel, and a soft insole170 for comfort and cushioning. The upper region 164 traverses the shoe150 from the heel to the toe. A padded toe region 172 protects thewear's toes. Note that in FIG. 7B, region 156 is surrounded by thehigher density region 174 or optionally, by high density regions 176,for improved lateral stability. Clearly, the region 156 may be formed ofvarious shapes and relative sizes, depending on the sport or surfaceagainst which it's intended to bear.

In the configuration shown in FIG. 4A, it is apparent that the insole104 increases the thickness of the forefoot region 30 changing the shoe102 from one which is plantarflex to a shoe assembly 100 which isdorsiflex. The inventors have learned that this presents challenges informing the portion of the upper 14 so as to accommodate the changingamount of space inside the shoe assembly 100 available to accommodatethe toes and the forefoot. Therefore, in another embodiment, shown inFIG. 8, insoles 104′ are used which increase the thickness of the heelportion 34 changing the shoe 110 from one which is of maximumdorsiflexion of about 15 degrees (using the lowest heel point situatedunder the calcaneum bone where the foot takes a rounded shape) to a shoeassembly 112 which is plantarflex or 0 degree declination (i.e.,barefoot posture). The thickness of the insoles 104′ varies by about2.5-3 mm per degree of dorsiflexion.

The embodiment of FIG. 8 ensures that the form of the toe region 62remains unchanged as insoles 104′ are changed. As the degree ofdorsiflexion is increased, the height of the heel portion isproportionally decreased without alteration of the portion of the insoleextending from the back of the cuneiform bones and the cuboid to thetoes. For example, in an embodiment configured to provide 4 degrees ofdorsiflexion, the insole of the shell 12_will have a plus/minusvariation of 10 mm between the thickness in the metatarsal areas and thelowest point of the heel.

In another embodiment, the insoles 104′ are designed so as to bestackable, lifting the heel in 2.5 mm to 15 mm increments whichrepresent from 1 to 6 degree changes in dorsiflexion. The dashed line108 indicates a possible location of the interface between two layeringinsoles 104″. The insoles 104″ are formed so that The first-installedinsole 104″ has a lower surface which conforms to the form of the shell12, and an upper surface formed to adapt to a wear's foot 40, and thesecond-installed insole 104″ formed to conform to the top surface of thefirst-installed insole, itself having a top surface that conforms to awearer's foot. This provides the wearer with the ability to select theangle of declination, and thus the degree of dorsiflexion. It should benoted that the insoles 104′ must also be constructed of a materialhaving a comparable compression factor with the shell 12, in order toensure the selected dorsiflexion performance in operation.

Still further, in order to create a shoe that does not appear, from theexterior to be a dorsiflex shoe, the side wall portion 22 rises up andsurrounds the heel area of the wearer and continues in a directiontoward the toe region 62 at an angle ⊖ which is less than dorsiflex thanthe maximum dorsiflex attainable in the shoe. In this embodiment, theangle ⊖ is in fact plantarflex, so that the dorsiflex configuration isonly apparent to the wearer.

The insoles 104′ are constructed anatomically and is constructed ofmaterials typically used for orthopedic applications in shoes, suchmaterials selected so that the tolerance of deviation due to materialexpansion is low, shape memory characteristics high, which high cyclingendurance in compression.

Referring now to FIG. 9A, a table is shown of varying embodiments of thepower plate 66, 162, 180, 182, 184, 186, and 190 of the invention,which, as indicated, extend from the toe to the metatarsal phalangeal(“MF”), to the cuniform bones, or to the heel, as the case may be. Notethat in power plates 186 and 190, a thinned portion 186′ and 190′,respectively, connect a forefoot region to a heel region. With powerplate 184, the special “S-shaped” form provides improved end-to-endresilience of the shoe 10 and further acts to improve the energyabsorbing capacity of the sole by elastic flexion.

Referring now to FIG. 9B, in an alternate embodiment, longitudinal slits200 may be molded or cut in the power plate 66 in order to better adaptthe sole's characteristics to a particular sport of interest. Inparticular, the bending moment of inertia of the power plate 66 may bevaried by selectively, depending on the sport, adding slits to the powerplate 66. In particular cases, more than one power plate may be usedwithin the same construction, insert molded parallel to eachother,partially overlapping or in separate lengthwise segments.

Referring now to FIGS. 10A-10B, a typical insole 104, 104′, for use withthe shoe 10 has an arch support 210. Only the cross-hatched portion 212need have a variable thickness.

In operation, a traditional shoe provides for flexing of the metatarsalphalangeal 20, in order, anatomically, to maintain a reasonablefootprint on the ground, to both improve traction and to reduce thestress on the wearer's toes 94. In fact, the metatarsal phalange 20 isthe only part of the foot 40 (ankle excluded) that is actually bendingduring walking. The inventors have found that by increasing thestiffness of the sole portion 24 in the forefoot region 30, and furtherby restraining the top of the foot 40 above the metatarsal phalangealregion 20 (restraining the foot against bending of the metatarsals), thelever of the foot is increased. When the length of the lever can beincreased, the moment is increased and thus the power output of the footis increased, which results in a lengthening of the stride whilerunning. The result is improved “toe off” and an extended range ofmotion, less energy depredation in the toe area and a more efficientstride.

Increased efficiency of the stride leads to a corresponding reduction instrenuous training protocol and improved technique, which, consequentlyresults in reduced injury risk often associated with overtraining.

In an advantage of the invention, the 5 degree dorsiflex angle 30produces a shoe 10, 10′ that appears to be significantly less clumsy,more natural and comfortable, and therefore, much more likely to bepurchased and used by amateur athletes as well as professional athletes.The invention provides a reverse, dorsiflex to the orientation of thefoot, to a level which experimentation has shown produces the maximumpower output, namely 5 degrees. In fact, the inventors have learned thatthere is no remarkable benefit to be gained by providing a shoe which agreater reverse dorsiflex incline of 5 degrees.

In another advantage, the fact that the angle of reverse incline islesser with the invention as compared to dorsiflex shoes of the priorart, means that less material is required in manufacture less materialequates to less cost in manufacture as well as a lower minimum weight tothe shoe.

In another feature, the sidewall of the shell 12 is formed so as to givethe impression that the shoe is a conventional plantarflex shoe.

In another advantage, the invention eliminates the need for themetatarsal-phalange joint to flex because the shoe itself reproduces themovement of this joint and the toes.

In an advantage, the invention substantially reduces energy loss due tometatarsal-phalangeal flexing during running and jumping.

In another advantage, the invention improves the capacity of the foot byimproving its efficiency while mininimizing the risk to harm to the footby selecting the materials of the shoe to absorb stress and byreproducing the rolling motion of the foot.

In a further advantage, the shoe is configured to receive insoles whichadjust the thickness of the rear of the shoe from extreme dorsiflex toplantarflex, thus avoiding morphological problems which occur where aninsole is designed so as to increase the thickness of the forwardportion of the sole from plantarflex to dorsiflex.

In another advantage, insoles may be stackably inserted into the shoe,thereby reducing the total bulk and weight of the assembly including allinsoles which interface therewith.

In an advantage, the shoe improves the capacity of the foot by improvingits efficiency. Thus, the risk of harm to the foot is minimized byselecting the materials of the shoe to absorb stress and by reproducingthe rolling motion of the foot.

In another advantage, the shoe configuration allows for improvedperformance of the plantar flexor muscles.

In another advantage, the invention increases the power output of arunner and of forces applied to the ground. The athlete is able to runfaster because stride length is increased and contact time of the footon the ground is decreased.

Multiple variations and modifications are possible in the embodiments ofthe invention described here. Although certain illustrative embodimentsof the invention have been shown and described here, a wide range ofmodifications, changes, and substitutions is contemplated in theforegoing disclosure. In some instances, some features of the presentinvention may be employed without a corresponding use of the otherfeatures. Accordingly, it is appropriate that the foregoing descriptionbe construed broadly and understood as being given by way ofillustration and example only, the spirit and scope of the inventionbeing limited only by the appended claims.

1. A high performance dorsiflexion shoe for enveloping a foot (40) of awearer, including the wearer's metatarsal-phalangeal joint (20), theshoe comprising (a) a sole portion (24) having a ground-contactingsurface (26), a forefoot region (30), a midfoot region (32) and a heelportion (34), and (b) a constraining device (16) above themetatarsal-phalangeal joint; wherein the forefoot region is made of ahigh density material, and has a thickness, measured in a directionperpendicular to the ground-contacting surface of the sole portion,greater than the thickness of the heel portion, thereby defining adorsiflexion shoe having a characteristic angle (a) of declination fromthe forefoot region to the heel portion; wherein the constraining devicesubstantially constrains a wearer's metatarsal-phalangeal joints frommovement when exercising, and wherein the forefoot region has a curvedform defined so as to further minimize flexion of themetatarsal-phalangeal joint during walking or running.
 2. The shoe ofclaim 1, wherein the sole portion (24) is a component of a shell (12)which includes sidewall portions (22) extending upwardly from the soleportion to a circumferential edge (13) which surrounds the wearer's foot(40).
 3. The shoe of claim 2, wherein the circumferential edge (13) ishigher in the heel region (34) than in the forefoot region (30), thusgiving the outward appearance of a plantarflex shoe.
 4. The shoe ofclaim 1, wherein the forefoot region (30) includes at least one hard,high density insert (66, 162, 180, 182, 184, 186, 190) formed to followthe curvature of the sole portion (24).
 5. The shoe of claim 4, whereinthe at least one insert (66, 162, 180, 182, 184, 186, 190) includesreinforcing ribs (90).
 6. The shoe of claim 4, wherein the at least oneinsert (66, 162, 180, 182, 184, 186, 190) includes slits (200) fordefining the bending moment of inertia of the insert.
 7. The shoe ofclaim 4, wherein the at least one insert (66, 162) extends from theforefoot region (30) to the midfoot region (32).
 8. The shoe of claim 4,wherein the at least one insert (66, 162, 180) extends from the forefootregion (30) to an area adjacent the cuniform bones of the wearer.
 9. Theshoe of claim 4, wherein the at least one insert (184, 186, 190) extendsfrom the forefoot region (30) to the heel portion (34).
 10. The shoe ofclaim 5, wherein the ribs (90) pass through a softer endo layer (92) andthus, present an exposed surface (91).
 11. The shoe of claim 10, whereinthe at least one insert (66, 162, 180, 182, 184, 186, 190) is molded ofa color different from the sole, so as to prominently expose the form ofthe ribs (90) on an outside surface (91) of the shoe (10).
 12. The shoeof claim 1, wherein the angle (a) of declination is within the range of1 degree to 15 degrees, preferably 5 degrees.
 13. The shoe of claim 1wherein the forefoot region (30) includes a reinforced, padded toeportion (64).
 14. The shoe of claim 1, wherein the heel portion (34) issubstantially comprised of a low density, viscous-like material.
 15. Theshoe of claim 1 wherein the forefoot region (30) has a varying thicknessdefining a ground contact surface (26) of a curved form which mimics thefunction of natural metatarsal-phalangeal flexion.
 16. The shoe of claim11, wherein the curved form includes a straight portion, extendingapproximately from the heel portion (34) to the forefoot region (30),and a curved portion (28), substantially tangentially extending from thestraight portion, and then curving upward about the toe.
 17. Anadaptable shoe assembly wherein the assembly includes: a shoe having asole portion (24) of a pre-determined angle of inclination, adapted toreceive an interchangeable insole (104, 104′); and at least one insolewhich inserts into the shoe, the assembly changing the posture of awearer's foot (40) from one angle in a range between dorsiflexion andplantarflexion to another angle in the range resulting in a shoe definedby an angle of declination different from the pre-determined angle. 18.The shoe of claim 17, wherein the sole portion (24) is a component of ashell (12) which includes sidewall portions (22) extending upwardly fromthe sole portion to a circumferential edge (13) which surrounds thewearer's foot.
 19. The shoe of claim 18, wherein the circumferentialedge (13) is higher in the heel region (34) than in the forefoot region(30), thus giving the outward appearance of a plantarflex shoe.
 20. Theshoe of claim 19, wherein the insole (104, 104′) includes threedimensional structures (120) which interface with a mating surface onthe sole so as to lock the insole and the sole together, thus minimizingrelative motion therebetween.
 21. The assembly of claim 17, wherein theshoe is of a substantially normal plantarflexion form in which themetatarsal-phalangeal restraining device (16) is adjustable over themetatarsal-phalangeal joints (20) of the wearer with or without aninsole (104, 104′) installed, and the foot-contacting portion (26) ofthe sole portion (24) of the shoe is of a form which suitably interfaceswith the foot (40) so that, when the insole is not installed, the shoefunctions as a conventional plantarflexion shoe.
 22. The assembly ofclaim 17, wherein the at least one insole (104) has a weight (106)selected to provide a particular level of energy consumption during use.23. The assembly of claim 17, wherein the assembly is adapted to receiveone of at least two insoles (104, 104′) which alternatively insert intothe shoe, providing the wearer with the ability to select the angle (α)of declination, and thus the degree of dorsiflexion.
 24. The assembly ofclaim 23, wherein the insoles (104, 104′) are of a thickness selected inthe range of between 2.5 mm and 15 mm, representing approximately 0 to 6degree changes in dorsiflexion.
 25. The assembly of claim 17, whereinthe assembly is adapted to receive at least two insoles (104″), stackedone on the other, a first-installed insole having a lower surface whichconforms to the form of the shell, and an upper surface formed to adaptto a wear's foot, and the second-installed insole formed to conform tothe top surface of the first-installed insole, itself having a topsurface that conforms to a wearer's foot, thus providing the wearer withthe ability to select the angle (β) of declination, and thus the degreeof dorsiflexion.
 26. The assembly of claim 25, wherein the insoles (104,104′) are of a thickness selected in the range of between 2.5 mm and 15mm, representing approximately 0 to 6 degree changes in dorsiflexion.27. The assembly of claim 17, wherein the assembly includes at least twoinsoles (104) of substantially differing weights, which alternativelyinsert into the shoe, providing the wearer with the ability to select aweight (106) to provide a particular level of energy consumption duringuse.
 28. The shoe of claim 17, wherein the forefoot region (30) includesat least one hard, high density insert (66, 162, 180, 182, 184, 186,190) formed to follow the curvature of the sole portion (24).
 29. Theshoe of claim 29, wherein the at least one insert (66, 162, 180, 182,184, 186, 190) includes reinforcing ribs (90).
 30. The shoe of claim 29,wherein the ribs (90) pass through a softer endo layer (92) and thus,present an exposed surface (91).
 31. The shoe of claim 30, wherein theat least one insert (66, 162, 180, 182, 184, 186, 190) is molded of acolor different from the sole portion (24), so as to prominently exposethe form of the ribs (90) on an outside surface of the shoe.
 32. Theshoe of claim 28, wherein the at least one insert (66, 162, 180, 182,184, 186, 190) includes slits (200) for defining the bending moment ofinertia of the insert.
 33. The shoe of claim 28, wherein the at leastone insert (66, 162) extends from the forefoot region to the midfootregion.
 34. The shoe of claim 28, wherein the at least one insert (180)extends from the forefoot region to an area adjacent the cuniform bonesof the wearer.
 35. The shoe of claim 28, wherein the at least one insert(182, 184, 186, 190)extends from the forefoot region to the heelportion.
 36. A high performance dorsiflexion shoe for enveloping awearer's foot, the shoe comprising a sole portion (24) having aground-contacting surface (26), a forefoot region (30), a midfoot region(32) and a heel portion (34), wherein the forefoot region includes ahard, high density insert (66, 162, 180, 182, 184, 186, 190) formed tofollow the curvature of the sole portion, wherein the heel portion ismade substantially of a soft, viscous-like material, the overallthickness of the sole portion being such that the angle (α) ondeclination is at most 0 degrees, and wherein the differences indeformation of the hard and the soft materials are defined so as toenable the sole portion to deform during exercise in a manner thatcreates the effect of a dorsiflexion shoe.